This invention relates to a driving apparatus for electric power circuit breakers having a substantially rectangular two-part housing one part of which serves to support and hold the drive parts and the other part of which forms the cover for the first part. Driving structures of this type, such as are described, for instance, in the German Auslegeschrift No. 15 40 439, are used primarily for medium-voltage power circuit breakers. They are, in general, three-pole breakers having three upright pole columns arranged side by side and fastened to the driving apparatus by means of pin-type insulators. Between the pin insulators and the driving apparatus, profiled sections, bars or similar parts may be provided for mechanical stiffening of the arrangement.
If the electrical switching capacity of a power circuit breaker of the type described is to be increased, greater mechanical driving energy is required because larger mechanical masses must be accelerated in the switching process. The use for this purpose of methods generally known in the art for scaling up the structure results, however, in enlargement of the driving structure in proportion to the larger driving energy. To avoid such enlargement and so, also, the greater weight of the driving apparatus, materials of greater strength may be used; the springs, shafts and latches may then be made with the same dimensions while accommodating the higher stresses. This undesirably increases the cost of the driving structure, however.
It is an object of the invention to avoid, at least in part, the increase in weight and costs accompanying an increase of the capacity of a circuit breaker driving apparatus of the present type by means of a novel structure.